Introduction Membrane Permeation System Experimental Section Presented By: Rich Dominiak Laura Kuczynski John Roszko

Introduction  Mass transfer through various membranes is receiving increased attention  Drug delivery through polymer membranes and human or animal skin has become a challenging research area  In vitro setups are used to make permeation measurements for membrane- moderated controlled release of drugs  The effect of the diffusion boundary layer on permeation has not been studied

Introduction  Permeation rate data can be easily distorted by the diffusion boundary layers on the membrane  The rate of drug permeation should be measured using a calibrated permeation cell  In this study The hydrodynamic characteristics of the an in-vitro membrane permeation cell developed by Chien and Valia were investigated Determine if it can be calibrated as a standardized in- vitro system

Membrane Permeation System  Membrane surface area – 0.64 cm 2  Star head magnetic stirrer  Donor and receptor reservoirs 3.5 mL capacity Completley enclosed Jacketed for temperature control

Experimental Section  Objective: To obtain the aqueous solubilities of benzoic acid in various PEG 400 solutions  Saturated solutions of benzoic acid in water with 0-40% PEG 400 were prepared by placing an excess of benzoic acid in test tubes with the PEG solutions  They were placed in a shaking water bath for 24 hours

Experimental Section  Filtered through 0.45 um Millipore filter  Diluted with solution medium that was used in the test tubes  Concentrations were analyzed using a UV/vis spectrophotometer  Viscosity was measured using and Ostwald capillary viscometer

Experimental Section  Diffusion coefficients were calculated from literature values based on the diffusivity in pure water at 25 C Wilke equation – x cm 2 /s  Thin benzoic acid disks were made by pouring fused benzoic acid into a metal mold positioned on a pill tile Mounted to permeation cell

Experimental Section  3.5 mL of each solution (previously made) were pipetted into the receptor compartment while the donor compartment remained empty  At time intervals, 20 uL were withdrawn and diluted to 10 mL samples  These were analyzed with the UV spectrophotometer